1. Field of the Invention
The present invention relates to a liquid ejecting head for ejecting a desired liquid, utilizing formation of bubble, a head cartridge using the liquid ejecting head, a liquid ejecting apparatus, a liquid ejecting method, a recording method, and a head used in these methods.
More particularly, the present invention relates to a liquid ejecting method and a recording method using a liquid ejecting head with a movable member arranged to be displaceable making use of generation of bubble.
The present invention is applicable to equipment such as a printer, a copying machine, a facsimile machine having a communication system, a word processor having a printer portion or the like, and an industrial recording device combined with one or more of various processing devices, with which recording is effected on a recording medium such as paper, thread, fiber, textile, leather, metal, plastic material, glass, wood, ceramic material, and so on.
In this specification, "recording" means not only forming an image of letter, figure, or the like having specific meaning, but also forming an image of a pattern having no specific meaning.
2. Related Background Art
A conventionally known ink jet recording method is the one in which a state of ink is changed to cause an instantaneous volume change (generation of bubble), so as to eject the ink through an ejection outlet by acting force resulted from the state change, whereby the ink is deposited on the recording medium to form an image thereon. As disclosed, for example, in U. S. Pat. No. 4,723,129, a recording device using this recording method usually comprises an ejection outlet for ejecting the ink, an ink flow path in fluid communication with the ejection outlet, and an electrothermal transducer as an energy generating means, disposed in the ink flow path, for ejecting the ink.
By this recording method a high quality image can be recorded at high speed and with low noise and such ejection outlets for ejecting the ink may be arranged in high density in a head for performing this recording method. Therefore, the recording method has a lot of excellent points; for example, the device compact in size can obtain an image recorded in high resolution and can also readily obtain a color image. Because of it, the ink jet recording method is now widely used in printers, copying machines, facsimile machines, or other office equipment, and even in industrial systems such as a textile printing device or the like.
With spread of use of the ink jet technology in products in wide fields, a variety of demands described below are increasing these years.
For example, an example of investigation to meet the demand to improve the energy use efficiency is optimization of the heat generating element such as adjustment of the thickness of a protection film. This technique is effective to an improvement in transfer efficiency of heat generated into the liquid.
In order to provide high-quality images, proposed were driving conditions for realizing the liquid ejection method or the like capable of performing good ink ejection based on high-speed ejection of ink and stable generation of bubble. From the standpoint of high-speed recording, proposed was an improvement in a configuration of flow passage in order to obtain a liquid ejecting head with high filling (refilling) speed of the liquid ejected, into the liquid flow path.
Among this configuration of liquid passage, the publication of Japanese Laid-open Patent Application No. 63-199972 or the like describes the flow passage structure as shown in FIGS. 1A and 1B. The flow passage structure and the head producing method described in this publication concern the invention accomplished noting the back wave occurring with generation of bubble (i.e., the pressure directed in the opposite direction to the direction toward the ejection outlet, which is the pressure directed to a liquid chamber 12). This back wave is known as loss energy, because it is not energy directed in the ejection direction.
The invention shown in FIGS. 1A and 1B discloses a valve 10 located apart from a bubble generation region formed by a heat generating element 2 and on the opposite side to the ejection outlet 11 with respect to the heat generating element 2.
In FIG. 1B, this valve 10 is illustrated as being produced by the producing method making use of a plate material or the like, having an initial position where it is stuck to the ceiling of the flow path 3, and dropping into the flow path 3 with generation of bubble. This invention is disclosed as the one for suppressing the energy losses by controlling a part of the back wave by the valve 10.
However, as apparent from investigation on the case where a bubble is generated inside the flow path 3 as retaining the liquid to be ejected in this structure, to regulate a part of the back wave by the valve 10 is not practical for ejection of liquid.
The back wave itself originally has no direct relation with ejection, as discussed previously. At the point when the back wave appears in the flow path 3, as shown in FIG. 1B, the pressure directly related to ejection out of the bubble is already ready to eject the liquid from the flow path 3. It is thus clear that to regulate the back wave, more accurately, to regulate a part thereof, cannot give a great effect on ejection.
In the bubble jet recording method utilizing the bubble generated by the heat generating element, on the other hand, heating is repeated while the heat generating element is in contact with the ink, which forms a deposit due to scorch of ink on the surface of the heat generating element. A large amount of the deposit could be formed depending upon the type of ink, which could result in unstable generation of bubble and which could make it difficult to eject the ink in good order. It has been desired to achieve a method for well ejecting the liquid without changing the property of the liquid to be ejected even if the liquid to be ejected is the one easily deteriorated by heat or even if the liquid is the one not easy to achieve adequate generation of bubble.
From this viewpoint, another proposal was made to provide a method to employ different types of liquids, a liquid (bubble generation liquid) for generating a bubble by heat and a liquid (ejection liquid) to be ejected, arranged to transmit the pressure upon generation of bubble to the ejection liquid and to eject the ejection liquid thereby, for example as disclosed in Japanese Laid-open Patent Applications No. 61-69467 and No. 55-81172, U. S. Pat. No. 4,480,259, and so on. In these publications, the ink as the ejection liquid is perfectly separated from the bubble generation liquid by a flexible film such as silicone rubber so as to keep the ejection liquid from directly contacting the heat generating element, and the pressure upon generation of bubble in the bubble generation liquid is transferred to the ejection liquid through deformation of the flexible film. By this structure, the method achieved prevention of the deposit on the surface of the heat generating element, an improvement in freedom of selection of the ejection liquid, and so on.